Neuroleptic effects in Tourette syndrome predict dopamine excess and acetylcholine deficiency.

Tourette syndrome (TS) may be characterized by relatively excessive CNS dopamine activity and by relatively deficient CNS acetylcholine activity. New evidence for this hypothesis derives from comparisons of neuroleptic effects in TS with neuroleptic ability to block in vitro and in vivo assays of dopamine and cholinergic muscarinic receptors. These data support the concept of dopamine hyperactivity in TS, possibly mediated by supersensitive dopamine type 2 receptors (which are not linked to adenylate cyclase). These data also suggest that cholinergic activity may be relatively deficient in TS, which is consistent with the dopamine-acetylcholine imbalance hypothesis of hyperkinetic movement disorders.